The Inclusion of Dietary and Medicinal Mushrooms into Translational Oncology: Pros and Cons at the Molecular Level

Mushrooms are valued for their nutritional qualities and have been used in traditional medicine since the Neolithic era. They exhibit various bioactivities, including antioxidant, hypocholesterolemic, immunomodulatory, and anticancer effects. The anticancer effects arise via direct action on tumor cells and indirect modulation of the immune system; the latter is the predominant mechanism. Numerous studies indicate that various mushroom species are potent immunostimulants because their cell wall polysaccharides and proteoglycans are recognized by intestinal immune cells. This enhances antitumor immunity through multiple molecular pathways. However, their direct effects on cancer cells are of questionable physiological relevance due to bioavailability constraints. Nevertheless, we hypothesize that the accumulation of non-absorbed polysaccharides in the gastrointestinal tract positions mushrooms as dual-action agents with the potential to treat colorectal cancer by providing indirect immunomodulation and direct local tumor suppression. Conversely, the direct anticancer effects of mushrooms are generally attributed to bioactive secondary metabolites that influence essential cellular processes, including signaling pathways, cell cycle regulation, apoptosis, autophagy, cellular migration, invasion, and cancer stem cell characteristics. Beyond these anticancer effects, clinical evidence suggests that certain mushroom-derived substances can improve survival outcomes for cancer patients and provide supportive care benefits in oncology, thereby improving quality of life. Specifically, mushrooms may mitigate the side effects of chemotherapy and radiotherapy, bolster immune function often suppressed by cancer treatments, and enhance overall well-being. In this review, we discuss the therapeutic benefits of dietary and medicinal mushrooms in cancer care, as well as unresolved challenges and future research directions.